Fitting windows in shed

[John Brown]

I am a bit confused re. breather membrane and fitting window frames. If I search the internet, I can find about 126 different opinions on how to do things.
I have some oak window frames that I am repurposing. I made a rough and ready cill with a sloping edge and a drip groove, which I have affixed to the bottom of the frames.
I am not particularly bothered about the top of the window frame, as it is tucked away under the eaves, so unless the rain is blown upwards it should be OK. Also, I guess the cladding can overlap the top of the frame.
I figure I will have vertical battens that bridge the join between the shed frame and the window frame and which butt up agains the ends of the cladding boards.
However, various internet sources say I should fold the Tyvek around the sides/not fold round the sides, fold over the bottom of the aperture/not fold over the bottom...
My inclination is to not fold any of the breather, and to seal any gaps with framing sealant.
Drawing was supposed to show cross section of window frame with dotted lines being studs, but it has been rotated by 90 degrees...
The photo is pointless, except that it proves I do actually have a shed build in progress.

 

[Mike G]

It doesn't much matter what you do. The only issue is finding something neat to do with the Tyvek, so I cut diagonals up from the corners of the openings, fold the Tyvek in, and trim off at the back edge of the timber frame. That leaves the corners as bare wood, but the window itself is fitted to the front edge of the opening, and sealed at that line, completely protecting the framing. A lining is then placed over that junction, leaving it about 3 inches back. It's one of those details that people worry about unnecessarily.

 

[John Brown]

Thanks, Mike.

John